Magnum 4K220 Switches Installation and User Guide (10/04)
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General information -
Auto-negotiation per-port for 802.3u-compliant switches occurs
when:
the devices at both ends of the cable are capable of operation at either 10
Mb or 100Mb speed and/or in full- or half-duplex mode, and can
send/receive auto-negotiation pulses, and . . .
-- when the second of the two connected devices is powered up*, i.e.,
when LINK is established for a port, or
-- when LINK is re-established on a port after being lost temporarily.
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NOTE
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some NIC cards only auto-negotiate when the computer system
that they are in is powered up. These are exceptions to the “negotiate at
LINK – enabled” rule above, but may be occasionally encountered.
When operating in 100Mb half-duplex mode, cable distances and hop-counts
may be limited within that collision domain. The Path Delay Value (PDV) bit-times
must account for all devices and cable lengths within that domain. For Magnum 4K-
Series switched ports operating at 100Mb half-duplex, the bit time delay is 50BT.
4.5
Auto-negotiation, full-duplex mode
Full-duplex Ethernet provides separate Transmit and Receive data paths,
enabling simultaneous bi-directional collision-free data movements on a port. The
network topology must be a “star” type, not a “bus” type. With full-duplex mode, the
cable distance is only limited by the physical layer line driver and cable attenuation.
There are no collision-domain restrictions or limitations.
The Magnum 4K-Series Switches perform half- or full-duplex mode auto-
negotiation independently on all switched ports. If the device or node on the other end
of a port’s attached cable supports F/H mode, auto-negotiation or is set to operate as
full-duplex, the Magnum 4K220 Switch will negotiate to run full-duplex. If the
attached device or node doesn’t support F/H mode, auto-negotiation (for example, if it
is a 10 Mb repeater or a standard 100Mb hub), the 4K220-Switch’s RJ-45 ports will
default to operate at half-duplex.
